The present invention concerns a device for closing a valve comprising an interior housing with an access opening for inserting or removing the probe of a measurement or detection apparatus, for example, a temperature measurement probe, without the need of disassembling either the closing device or the valve, while permitting the valve to remain closed.
Although not limited in scope to such use, the closing device of the invention is preferably intended for a drainage valve of a reactor, a storage vat, a column, or other container.
In order to control a chemical reaction, it is often essential to measure the temperature of the reactive environment inside the reactor. Not only does this information make it possible to retroactively adjust the means for heating or cooling the reactor to attain or maintain the desired temperature, but it also ensures that the chemical reaction is proceeding properly. In practice, a sharp rise in temperature often signifies that the reaction has gone awry, and quick detection of such a situation may be critical for the safety of employees, equipment, and the environment.
For this reason, reactors or other chemical containers are often equipped with a device for measuring the temperature of their contents.
In order to avoid problems with seals, construction and cost in conventional temperature measurement systems that use a penetrating probe surrounded by a thermometric casing placed in a supplemental tube in the reactor, the prior art has proposed a more satisfactory measurement device using a contact measurement probe.
With this device the temperature probe is maintained in contact with a locally thinned area of the reactor wall and it measures content temperature through the wall. This eliminates the need to form an opening extending into the core of the reactor.
In a conventional system, this contact temperature probe is often placed at the level of the reactor drainage valve. Therefore, it is mounted inside the closing device on the drainage valve, said device being movable between an upper position and a lower position corresponding to the opening and closing the valve, respectively.
The probe may be integrated with the interior of the blocking head of the closing device near its upper wall during construction, or it may be housed within a hollow interior portion in the blocking head against the internal surface of its upper wall. The conductive wires, connecting the probe to the measurement device, generally pass through the shaft of the closing device.
This location confers the following advantages:
First, it uses a previously existing opening in the reactor. Thus, no costly reactor modifications are necessary. Only the valve closing device needs to be adapted, which is far less expensive.
Second, since the drainage valve constitutes the lowest point on the container, the probe is always surrounded by liquid, whatever the level of liquid in the container. It is located in an area far away from thermal surface flux and in a place where the reactive environment is homogeneous, since it is generally well mixed by an agitator. Moreover, since the blocking head extends slightly inside the reactor, the temperature being measured is not artificially raised or lowered by proximity to the outside environment or the double wall sometimes used. Thus, the temperature that is measured is representative of the temperature of the entire reactor contents.
Due to the development of ISO-type quality controls, these temperature probes must meet new requirements. They must be adjusted regularly, requiring removal from their operating position inside the reactor.
In prior art systems, this frequent removal is problematic. In order to remove the probe from its placement, it is actually necessary to completely disassemble the drainage valve in order to remove the closing device surrounding the probe. Obviously, the reactor must be completely emptied prior to performing these operations.
For this reason, a simple recalibration of the temperature measurement probe becomes synonymous with one to two days of lost productivity while the reactor is completely emptied and cleaned, the drainage valve and its seal are removed, as well as the measurement probe, all in compliance with safety standards; next, the probe must be recalibrated, the various elements reattached, and the reactor refilled, before production can resume. For these reasons, a simple, routine operation becomes extremely costly and unprofitable to the industry.
The goal of the present invention is to offer ready access from the exterior to the temperature measurement probe positioned inside the movable closing device on the drainage valve, and to quickly and easily remove and reposition it without detaching the valve and the seal and without interfering with the progress of the reaction inside the reactor.
To resolve this technical problem, the principle of the invention consists of providing a valve closing device, particularly for a drainage valve, with an interior housing designed to hold the probe or the detector of a measurement or detection apparatus, having an opening located on a portion of the closing device that is accessible when it is in the operating position inside the valve, providing access to the interior housing, and allowing insertion or removal of the probe or the detector without having previously detached the valve or its closing device.
A contact temperature measurement probe with a flexible shaft can thus be easily introduced into the interior housing of the closing device of the invention through this access opening, until it contacts the upper wall of the blocking head of the closing device, which is preferably a thinner portion, through which it measures the temperature of the reactive environment.
In the same way, it can be simply and quickly withdrawn for if, for example, replacement, adjustment or calibration is required, with no effect on the reactor""s contents and without any need to detach or re-attach the valve or its closing device.
The device of the invention is, therefore, especially advantageous because it saves valuable time but still uses a conventional temperature measuring contact probe located within the closing mechanism of the drainage valve.
The closing device of the invention is easily manufactured and scarcely more expensive than prior art closing devices. It can be attached to any type of valve, either a drainage valve or some other type, and used on any type of reactor, columns, storage vats, containers or the like. Furthermore, most types of existing measurement or detection contact probes may be easily adapted to it.